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The effect of negative excess pore-water pressure on the stability of excavated slopes


Ghadrdan, M and Shaghaghi, T and Tolooiyan, A, The effect of negative excess pore-water pressure on the stability of excavated slopes, Geotechnique Letters, 10, (1) pp. 20-29. ISSN 2045-2543 (2020) [Refereed Article]

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Copyright 2019 ICE Publishing

DOI: doi:10.1680/jgele.19.00040


Generation of negative excess pore-water pressure (NEPWP) due to the excavation of saturated soils under undrained conditions and the dissipation that follows over time may result in different short- and long-term slope instability. The NEPWP generated due to excavation gradually decreases towards equilibrium or, in some cases, steady seepage. Hence, total pore-water pressures immediately after excavation are lower than the ultimate equilibrium values, leading to a reduction of the average effective stresses in the slope and subsequently threatening stability in the long term. In this research study, the stability of three benchmark civil and mining excavations has been studied, considering the effects of the generation and dissipation of NEPWP. A series of numerical simulations are conducted to determine the role of in situ stresses and time in NEPWP dissipation as well as the consequent effects on the stability of the excavated slopes. To conduct a realistic time-dependent transient analysis, fully coupled hydro-geomechanical formulation has been employed. Results show that in general, higher removal of stress levels lead to higher NEPWP generation and higher factor of safety values in the short term. Thereafter, the dissipation of NEPWP threatens the long-term stability of the excavation.

Item Details

Item Type:Refereed Article
Keywords:excavation, pore pressures, time dependence
Research Division:Engineering
Research Group:Civil engineering
Research Field:Civil geotechnical engineering
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in engineering
UTAS Author:Tolooiyan, A (Dr Ali Tolooiyan)
ID Code:135232
Year Published:2020
Web of Science® Times Cited:1
Deposited By:Engineering
Deposited On:2019-10-08
Last Modified:2021-03-16
Downloads:44 View Download Statistics

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